【正文】 高壓鑄造快速抽真空方法研究 重慶大學(xué)碩士學(xué)位論文 學(xué)生姓名： 干雪梅 指導(dǎo)老師： 龍思遠(yuǎn) 教授 專 業(yè)： 材料加工 學(xué)科門類： 工學(xué) 重慶大學(xué)材料科學(xué)學(xué)院 二零一一年 四 月 Research and Development of Fast Vacuuming for Highpressure Casting A Thesis Submitted to Chongqing University in Partial Fulfillment of the Requirement for the Degree of Master of Engineering By Xuemei Gan Supervisor: Long Major: Material Engineering College of Materials Science and Engineering of Chongqing University, Chongqing, China April, 20xx重慶大學(xué)碩士畢業(yè)論文 中文摘要 I 摘 要 隨著 鑄造技術(shù)的發(fā)展 ， 市場(chǎng)對(duì)鑄件產(chǎn)品質(zhì)量要求越來(lái)越高 ，真空輔助 鑄造工藝得 到 越來(lái)越廣泛 的應(yīng)用 。 抽 真空系統(tǒng)是真空 鑄造 技術(shù) 有效 應(yīng)用的關(guān)鍵 設(shè)備 ，其可靠性和穩(wěn)定性直接影響鑄件質(zhì)量。 高壓鑄造用 真空系統(tǒng)的關(guān)鍵 技術(shù) 之一 是 如何使型腔 內(nèi)氣體 在極短時(shí)間內(nèi) 排出 ；二是如何在充型 過(guò)程中 及時(shí)關(guān)閉真空通道，避免金屬液進(jìn)入真空系統(tǒng) 。 目前市場(chǎng)上已有 高速有效的 國(guó)外產(chǎn)品如方達(dá)瑞真空壓鑄系統(tǒng) 能快速對(duì)型腔抽真空 ， 型腔真空度在充型后期 可達(dá) 100mBar，并且及時(shí)的關(guān)閉真空通道，有效 阻止金屬液進(jìn)入真空系統(tǒng) 造成堵塞 。但是其 成本較高，價(jià)格昂貴， 而國(guó)內(nèi) 抽 真空 系統(tǒng)可靠性低 ， 充型末期型腔真空度一般為 500mBar，性能和鑄件質(zhì)量不穩(wěn)定。 本課題是在 研究 現(xiàn)有真空 鑄造 技術(shù)的基礎(chǔ)上， 針對(duì)現(xiàn)有 國(guó)外高速有效 抽 真空 輔助 系統(tǒng)成本 過(guò) 高，而國(guó)內(nèi)真空系統(tǒng) 減小鑄件氣孔缺陷效果不明顯的瓶頸， 以 鎂合金輪轂 真空高壓鑄造生產(chǎn)為研究對(duì)象，進(jìn)行了系統(tǒng)的理論研究和技術(shù)開(kāi)發(fā)，取得了以下成果： 1. 在深入分析現(xiàn)有商用真空技術(shù)的基礎(chǔ)上，根據(jù)高壓鑄造工藝特征，提出高速實(shí)現(xiàn)模具型腔抽真空的 新 思路和 新 方法； 2. 用型腔排氣數(shù)學(xué)模型討論了工藝參數(shù)對(duì)型腔真空度的影響，為模具抽真空通道的設(shè)計(jì)與優(yōu)化真空泵和真空罐組 合奠定了理論基礎(chǔ)； 3. 開(kāi)發(fā)了真空實(shí)時(shí)檢測(cè)硬件系統(tǒng)和檢測(cè)程序，實(shí)現(xiàn)了型腔真空度與抽氣時(shí)間曲線的實(shí)時(shí)檢測(cè)顯示； 4. 提出了真空通道快速開(kāi)關(guān)液壓系統(tǒng)和實(shí)現(xiàn)方法，形成了擁有自主知識(shí)產(chǎn)權(quán)、性能穩(wěn)定可靠的真空壓鑄系統(tǒng)，并通過(guò)了鎂合金摩托車輪轂的實(shí)驗(yàn)性生產(chǎn)驗(yàn)證； 5. 對(duì)常規(guī)和真空高壓鑄造鎂合金輪轂進(jìn)行的組織和性能對(duì)比分析結(jié)果表明：采用真空輔助工藝后，鑄件內(nèi)氣孔缺陷基本消除，可以進(jìn)行固溶熱處理；真空高壓鑄造鎂合金輪轂的力學(xué)性能較普通輪轂有明顯的提高。 本課題研制的 抽 真空系統(tǒng) 具 廣泛的適應(yīng) 性，可 滿足 除輪轂外的 其他鑄件的真空高壓鑄造生產(chǎn)的 要求。 關(guān)鍵詞 ： 鎂合金 ，真空壓鑄，真空度， 組織性重慶大學(xué)碩士學(xué)位論文 英文摘要 II Abstract With the development of casting technology, the demand of market for quality of casting products is increasing, The vacuumassisted casting process have been applied more extensive. Vacuum system is the key factor of vacuum casting technology, stability and reliability of vacuum system will affect the vacuum casting technology directly. One of the key technologies for vacuum casting technology is how to pump air of cavity in a very short time。 another is to close vacuum channel in time so as to avoid leaking liquid metal into vacuum system when filling mold finished. At present, the systems made by Fondarex occupy the market, which has stable and high pumping ability to make the pressure of cavity to be 100 mbar, also close the vacuum channel in time. But this system requires high equipment purchase and maintenance costs. Compared to the former, the vacuum systems in home have low reliability, its performance and the quality of vacuum die castings are not stable. Combining with the base research of vacuum casting technology which is expensive or unreliable, this paper makes magnesium alloy wheel with highpressure vacuum casting productions to be the research object, studies theoretical research and technology development, and gains some results as follows: 1. Based on the analysis of the existing mercial vacuum technology, according to the features of highpressure casting process, the new idea and methods of fast vacuuming have been proposed。 2. The process parameters affecting the cavity vacuum degree have been analyzed through cavity exhaust mathematical model, to make the theoretical basis for the design of exhaust channel and the bination of vacuum pump with vacuum tank。 3. The innovated and realtime system of detecting for cavity vacuum degree have been developed, bing the transmitter and collector, the curve of cavity vacuum degree and pumping time was displayed, to achieve the realtime detection and conformity。 4. Fast switching of hydraulic system in exhaust channel and its 重慶大學(xué)碩士學(xué)位論文 英文摘要 III implementation have been proposed, vacuum casting system which has independent intellectual property right and high reliability has been developed and validated by experimental production of magnesium alloy motorcycle wheel。 5. The results of parative analysis between the ordinary and vacuum magnesium alloy motorcycle wheel castings on the microstructure and mechanical properties shows : pared with ordinary magnesium alloy wheel castings, the size and amount of gas defects have been improved apparently, and can use heat treatment to improve casting’s quality。 the mechanical performance of vacuum casting also have been enhanced obviously. The vacuum system of this paper has wide range of adaptability, can be expanded to other castings besides motorcycle wheel to meet the production requirement of vacuum highpressure casting. key word: magnesium alloy， vacuum die casting, vacuum degree, anization and performance. 重慶大學(xué)碩士學(xué)位論文 目錄 IV 目 錄 摘 要 ....................................................................................................................... I Abstract ................................................................................................................... II 1 緒論 ....................................................................................................................... 1 ........................................................................ 1 .................................................................................................... 4 ............................................................................... 6 國(guó)內(nèi)外真空壓鑄技術(shù)的發(fā)展 .................................................................... 6 各種真空壓鑄系統(tǒng)分析比較 ..................................................................... 7 真空壓鑄技術(shù)廣泛應(yīng)用的瓶頸 ................................................................ 12 本課題研究的意義 ..............